Re: [PATCH v2 8/8] nptl: rseq failure after registration on main thread is fatal

[Szabolcs Nagy <szabolcs.nagy@arm.com>]

The 12/07/2021 14:04, Florian Weimer via Libc-alpha wrote:
> This simplifies the application programming model.
> 
> Browser sandboxes have already been fixed:
> 
>   Sandbox is incompatible with rseq registration
>   <https://bugzilla.mozilla.org/show_bug.cgi?id=1651701>
> 
>   Allow rseq in the Linux sandboxes. r=gcp
>   <https://hg.mozilla.org/mozilla-central/rev/042425712eb1>
> 
>   Sandbox needs to support rseq system call
>   <https://bugs.chromium.org/p/chromium/issues/detail?id=1104160>
> 
>   Linux sandbox: Allow rseq(2)
>   <https://chromium.googlesource.com/chromium/src.git/+/230675d9ac8f1>
> ---
> v2: New patch.  Tested with Firefox 94.0 on Fedora 35.

looks good.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

> 
>  nptl/pthread_create.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> index 4608fd9068..c097fc54e6 100644
> --- a/nptl/pthread_create.c
> +++ b/nptl/pthread_create.c
> @@ -370,7 +370,8 @@ start_thread (void *arg)
>    /* Register rseq TLS to the kernel.  */
>    {
>      bool do_rseq = THREAD_GETMEM (pd, flags) & ATTR_FLAG_DO_RSEQ;
> -    rseq_register_current_thread (pd, do_rseq);
> +    if (!rseq_register_current_thread (pd, do_rseq) && do_rseq)
> +      __libc_fatal ("Fatal glibc error: rseq registration failed\n");
>    }
>  
>  #ifndef __ASSUME_SET_ROBUST_LIST
> -- 
> 2.33.1
>